Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred income tax expense (benefit):
Total deferred expense (benefit)	$ 31	$ 20	$ 213
Total income tax expense (benefit)	170	360	110
Houston Electric
Current income tax expense (benefit):
Federal	(26)	23	22
State	34	16	22
Total current expense (benefit)	8	39	44
Deferred income tax expense (benefit):
Federal	159	86	31
Federal	(26)	23	22
State	1	0	1
Total deferred expense (benefit)	160	86	32
Total income tax expense (benefit)	168	125	76
CERC Corp
Deferred income tax expense (benefit):
Total deferred expense (benefit)	(41)	178	101
Total income tax expense (benefit)	(26)	236	76
Consolidated
Current income tax expense (benefit):
Federal	106	294	0
State	33	46	(28)
Total current expense (benefit)	139	340	(28)
Deferred income tax expense (benefit):
Federal	119	16	78
Federal	106	294	0
State	(88)	4	60
Total deferred expense (benefit)	31	20	138
Total income tax expense (benefit)	170	360	110
Consolidated | CERC Corp
Current income tax expense (benefit):
Federal	12	30	0
State	3	28	(25)
Total current expense (benefit)	15	58	(25)
Deferred income tax expense (benefit):
Federal	95	164	67
Federal	12	30	0
State	(136)	14	34
Total deferred expense (benefit)	(41)	178	101
Total income tax expense (benefit)	(26)	236	76
Discontinued Operations
Current income tax expense (benefit):
Federal	0	0	91
State	0	0	35
Total current expense (benefit)	0	0	126
Deferred income tax expense (benefit):
Federal	0	0	127
Federal	0	0	91
State	0	0	(52)
Total deferred expense (benefit)	0	0	75
Total income tax expense (benefit)	$ 0	$ 0	$ 201